Finally it is well to recognize that there is a vast sum of influences governed by no ascertainable principle at all, which go to assign the individual his place in the class system. After allowing for inheritance and for everything which can fairly be called selection (that is, for all definite and orderly interaction between the man and the system), there remains a large part which can be assigned only to chance. This is particularly true in the somewhat tumultuous changes of modern life. When a class is somewhat strictly hereditary, we may call it a caste—a name originally applied to the hereditary classes of India, but to which it is common, and certainly convenient, to give a wider meaning. Perhaps the best way to understand caste is to open our eyes and note those forces at work among ourselves which might conceivably give rise to it. On every side we may see that differences arise, and that these tend to be perpetuated through inherited associations, opportunities and culture. The endeavor to secure for one’s children whatever desirable thing one has gained for oneself is a perennial source of caste, and this endeavor flows from human nature and the moral unity of the family. If a man has been able to save money, he anxiously invests it to yield an income after his death; if he has built up a business, it is his hope that his children may succeed him in it; if he has a good handicraft, he wishes his boys to learn it. And so with less tangible goods—education, culture, religious and moral ideas—there is no good parent but desires his children to have more than the common inheritance of what is best in these things. It is, perhaps, safe to say that if the good of his children could be set on one side and the good of all the rest of the world over against it on the other, the average parent would desire that evil might befall the latter rather than the former. And much of the wider social spirit of recent times comes from the belief that we cannot make this separation, and that to secure the real good of our children we must work for the common advancement. That this endeavor to secure a succession in desirable function is not confined to the rich we may see, for instance, in the fact that labor unions often have regulations tending to secure to the children of members a complete or partial monopoly of the opportunities of apprenticeship. In Chicago, not long since, only the son of a plumber could learn the plumber’s trade.